The origins of Jupiter's Galilean moons is a long-standing mystery. But new research suggests a promising pathway for how they may have formed. From bottom to top is Io, Europa, Ganymede, and ...

New research shows auroras can also be seen on the Galilean moons of Jupiter: hypervolcanic Io, icy Europa, quirky Callisto and gigantic Ganymede. Auroras exist throughout the cosmos, but often in ...

Four of Jupiter's moons: Io, Europa, Ganymede and Callisto — known as the Galilean moons — were the first celestial objects to be discovered orbiting an object other than the sun or Earth when ...

Close-up of the craters and furrows on Ganymede's surface. Credit: NASA/JPL-Caltech/SwRI Aside from being the biggest of Jupiter's 95 moons, Ganymede is best known for its axial tilt and deep ...

This montage shows views of Jupiter's four 'Galilean moons' as captured by the LORRI camera system on NASA's New Horizons spacecraft in 2007 as it picked up extra momentum for its target, the dwarf ...

Jupiter’s largest moons, known as the Galilean moons, are known not only for their size but for their unique features. Discovered in 1610 by Galileo Galilei, these moons—Ganymede, Callisto, Io ...

Jupiter's four brightest moons — Ganymede, Callisto, Europa and Io — are similar in size to our own moon, and orbit the planet from 1.8 to 16.7 days.

Jupiter's four best-known moons are the Galilean moons, discovered by Galileo Galilei in 1610. They are named Ganymede, Callisto, Io and Europa, after figures in Greek mythology associated with ...

The two Galilean moons of Io and Europa (left to right) can also be seen. (CORBIS/Corbis via Getty Images) On Jan. 7, 1610, Galileo discovered four moons revolving around Jupiter — a discovery ...

The easiest ones to see are Ganymede and Callisto because they orbit farther from Jupiter and better escape its glare. These miniatures show the layout of Jupiter's moons around 8 p.m. Central ...